In an optical communication system, it is typically necessary to couple an optical fiber to an opto-electronic transmitter, receiver or transceiver device and to, in turn, couple the device to an electronic system such as a switching system or processing system. These connections can be facilitated by modularizing the transceiver device. Various transceiver module configurations are known. For example, the optical transceiver module 10 illustrated in FIG. 1 has a standard configuration or form commonly referred to as a Small Form Factor (SFF) or SFF-Pluggable (SFP) format. Transceiver module 10 includes a metallic module housing 12 in which are housed opto-electronic elements, optical elements, and electronic elements, such as one or more light sources (e.g., lasers), light sensors, lenses and other optics, digital signal driver and receiver circuits, etc. The front end of transceiver module 10 further includes a transmitter receptacle 14 and a receiver receptacle 16 into which optical fiber cables (not shown) are pluggable. The optical cable plug or connector body (not shown) can be of the standard type known as an LC connector, which has a squarish profile corresponding to the shape of receptacles 14 and 16 and a width of approximately one-quarter inch. Although not shown in FIG. 1 for purposes of clarity, transceiver module 10 can be plugged into a bay in the chassis or cage of an electronic system by inserting the rear end of transceiver module 10 into a bay opening in the cage and latching transceiver module 10 in place. A bail latch 18 facilitates latching transceiver module 10 and, when flipped to an extended position (not shown), serves as a handle by which a person can grip transceiver 10 to extract it from the cage.
Transceiver module size is of concern in the art. The width of housing 12 is substantially dictated by the two side-by-side receptacles 14 and 16. That is, housing 12 is at least as wide as two LC connectors. Multiple transceiver modules of this type can thus be plugged into a cage panel at a pitch on the order of about every one-half inch. That is, the electronic system cage can have on the order of one bay for receiving on the order of one transceiver module for every one-half inch of cage width. Among other drawbacks of arranging adjacent transceiver modules so densely is that bail latch 18 may be difficult to grasp.
Transceiver module cooling is another concern in the art. The heat emitted by the electronics and opto-electronics in transceiver module 10 in operation is commonly conducted away from transceiver module 10 by metallic portions of the cage bay in which transceiver module 10 is plugged. Heat sinks can be included in the cage to dissipate this heat. Alternatively or in addition, the sides, top or bottom of housing 12 can include apertures to promote cooling air flow into and out of housing 12. Providing adequate cooling is challenging in instances in which many transceiver modules are arranged closely together in the cage.